mineral

Quartz with Iron Staining

Silicon Dioxide (SiO2) with Ferruginous Oxides

Hardness: 7 (Mohs scale); Color: Grayish-white with orange-brown iron spots; Luster: Vitreous to dull; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65

Hardness: 7 (Mohs scale)
Color: Grayish-white with orange-brown iron spots
Luster: Vitreous to dull

Identified May 4, 2026More mineral →

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Physical properties

Formation & geological history

Quartz forms by crystallization from molten magma or precipitation from hot hydrothermal veins. The orange staining is a secondary process where iron-rich water infiltrates micro-cracks and oxidizes over geologic time.

Uses & applications

Commonly used as construction aggregate, in industrial glass making, and for amateur rock collecting. Larger, clearer specimens are used in jewelry.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. The 'rust' spots are often Limonite or Goethite, which are iron oxide minerals.

Field identification & locations

Identify in the field by its ability to scratch glass and its lack of cleavage. Look for the characteristic orange-brown 'stains' that cannot be easily washed off. Commonly found in riverbeds and mountainous terrain.

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